This invention relates to a postage meter and more particularly to a drive system in a postage meter for driving a platen, a priming pump, and a wiping mechanism.
Postage meters which imprint an indicia on a mailpiece or a label to be subsequently placed on a mailpiece have been used for approximately the last 75 years. The indicia is used in lieu of stamps and serves as evidence that postage has been paid. Moreover, since the indicia is compatible with postal service processing equipment, its handling can be expedited as compared to stamps. Thus, the postal service offers discounts to mailers using postage meters that print the indicia and additional identifying data which can be read by postal automated equipment. Typically, however, traditional postage meters, whether functioning as a stand-alone unit or as part of a mailing machine, were utilized by medium-sized and large-sized businesses having a fairly large and continuous stream of outgoing mail. Due to the costs of manufacturing these traditional postage meters the price to the consumer, as either a rented unit or a procured unit, would often preclude very small businesses from obtaining such a postage meter. That is, these small businesses couldn't justify the cost as compared to simply applying stamps to their mailpieces. However, throughout the world and particularly in the United States, a growing number of small office and home office (SOHO) businesses are being formed. It is anticipated that this segment of the business market will be the fastest growing segment in the years to come. While the SOHO businesses still are concerned about the expense associated with obtaining a postage meter, they often want to create the impression that their business is just as professional as the medium and large-sized businesses. One way of doing this is by sending mailpieces having a printed indicia or a printed indicia together with the company's personalized advertising slogan in lieu of applying postage stamps to their mailpieces. Accordingly, what is needed for the SOHO business market is a low cost postage meter product.
With the advancement of digital printing technology, such as inkjet printers, the cost associated with producing a printing apparatus have been reduced. Moreover, with the advancements in electronics and the miniaturization of electronic components, the efficiency, cost, and footprint of postage meters can all be reduced. However, the postage meter still relies on a number of mechanical components in order to ensure that continued repetitive good quality printing can be accomplished by, for example, an inkjet printing device. That is, with an inkjet printing apparatus the distance between the recording medium being printed on and the printhead nozzles must be precisely controlled in order to ensure a good print quality. Moreover, inkjet printers are subject to certain problems that did not exist with the previous printing technologies used in meters. The small ink ejection nozzles which are used in inkjet printers to expel drops of ink in a dot-matrix pattern on the recording medium are subject to becoming 1) clogged by dirt or paper dust, 2) deprimed to due the entrapment of air within the nozzle or the ink supply line leading from the nozzle to the ink supply, and 3) clogged if they are not used over an extended period of time such that the ink resident in the nozzles dries up.
To control the precise gap between the nozzles and the mailpiece, a movable platen can be used to properly position the mailpiece for printing thereon. Additionally, as is known in the art, a priming pump can be connected to a printhead maintenance station for drawing a vacuum on the nozzles when they are in a non-printing position in order to draw ink through the nozzles to remove contaminants, dried ink, or air which may be contained therein. Furthermore, a wiper blade can be used to wipe across the nozzles to remove excess ink and contamination from around the nozzle openings or the orifice plate within which the nozzles have been formed.
In previous inkjet printing devices, such as typewriters, it has been known to use a separate motor to drive the priming pump and a separate motor to properly position a wiper for wiping the nozzles. Moreover, in postage meters it is known to use a dedicated motor for the purpose of raising and lowering a platen. However, if three such motors were used in a low cost postage meter they would add to the footprint of the meter and drive up the cost of the postage meter. Accordingly, what is needed is a drive system in a postage meter which can be used to accomplish a plurality of the functions discussed above while minimizing the number of motors required. Ideally, this inventive drive train system should be capable of raising the platen, driving the priming pump, and positioning the wiper blade.